This is a broad program in investigation of molecular structure and genomes of several viruses and mechanisms involved in the regulation of expression of the genomes. Major portions of the program include characterization of biological variants of ABV virus, complete molecular characterization of SV40 virus, characterization of proteins of papova virus, purification of human interferon, study of the mechanisms of genetic recombination, studies in immunological viruses, study of the regulation of T7 phage gene expression, studies of SV40 gene expression in transformed cells.